Evaluation of the LMA Position Using Ultrasound in Pediatric Patients
Introduction: Although the LMA insertion is not difficult and majority of the cases with LMA fare well in ventilation, the FOB assessment demonstrates a high incidence of LMA malpositioning. The LMA must be seated at the laryngeal inlet with the occlusion of esophageal inlet by the inflated tip. When we meet the signs of LMA malposition, we then reinsert the LMA. The laryngoscopic grading of Rowbottom et al. is commonly used for LMA position, but the rotated degree of LMA was not considered in that grading. We hypothesized that the LMA can affect the position of the arytenoids/thyroid cartilages and it may be detected on ultrasound. This study was designed to assess the predictability of the rotated LMA according to the position change of arytenoids/thyroid cartilages using ultrasound.
Methods: Children, aged 1 ms - 6 years, undergoing infraumbilical surgery were enrolled to this study. Ultrasound was performed on supraglottic and vocal cords area before and after LMA insertion. Transverse images were obtained on end-expiratory phase. LMA-position was evaluated with Bonfils fiberscopy. Position grading was made as usual. If grade >3 was showed, LMA was repositioned while fiberscopic watching. If the face of LMA was rotated to one-side, the LMA was rotated to the opposite side a little. The ultrasound findings of pre- and post-LMA were compared. On fiberscopic images, conventional LMA grade and the degree of rotation were measured.
|Study Design:||Observational Model: Cohort
Time Perspective: Cross-Sectional
- changes of Ultrasound image of upper airway after Fiberoptic bronchoscopic grade of LMA insertion. [ Time Frame: After the induction of general anesthesia, ultasound image was gained before and after the LMA insertion. Fiberoptic bronchoscpy was done after the LMA insertion. ] [ Designated as safety issue: No ]
|Study Start Date:||January 2012|
|Study Completion Date:||July 2012|
|Primary Completion Date:||July 2012 (Final data collection date for primary outcome measure)|
Ultrasound exam of upper airway
Following Internal Review Board approval(4-2011-0800) and written informed consent, total 100 patients(ASA I and II children aged 1 month to 6years) undergoing infra-umblicular urologic surgeries were included in the study. Children with upper respiratory tract infection, restricted mouth opening, congenital heart disease and those at risk for aspiration were excluded.
Procedure: Ultrasound exam of upper airway
LMA-position was evaluated with fiberoptic laryngoscopy. The ultrasound findings of pre- and post-LMA were compared.